In construction operations where sections of intersecting pipe are to be interconnected by welding, it is typical in the industry to employ a curved pipe section which is typically referred to as a "tube turn." Tube turns are typically manufactured with bends of 90.degree. and 45.degree., thereby allowing connection of pipes that intersect in normal relation to one another, and also facilitate interconnection of pipes that intersect at an included angle of 135.degree.. In many cases, however, it is desirable that straight pipe sections intersect at included angles of other than 90.degree. or 135.degree., and, in such case, it is necessary for workmen to cut the tube turn such that the included angle thereof is as desired. Since tube turns are formed to define a circular cross-sectional configuration throughout the length thereof and are formed to define a smoothly curved partially circular segment that is generated about a point of concentricity, the workmen must calculate the angular modification of the 45.degree. or 90.degree. tube turn in order to cut the tube turn along a line radiating from the point of concentricity of the tube turn. Since apparatus is typically unavailable in the field for calculating angular modification of the tube turn in this manner, a typical field solution for accomplishing the desired result is for workmen to place the tube turn in assembly with one of the pipes to which it is to be connected. The other pipe is then oriented in appropriate angular relation relative to the tube turn, and with the center line of the pipe in intersecting relation with the curved center line of the tube turn. A straight-edge is then laid along the intersecting pipe in parallel relation with the axis of the pipe and is brought into contact with the tube turn and this point of contact is marked. Numerous other points of contact will be established in similar manner and the result will be the layout of a cut line that will be properly oriented in relation to the end of the intersecting pipe. Obviously, this layout procedure is difficult and time consuming to accomplish in the field and requires that the workmen involved be highly skilled in order to layout and cut the tube turn in proper manner for connection thereof to the interconnecting pipe. Moreover, the cut that is made on the tube turn must be beveled such that the resulting tube turn end is properly beveled in order that registry thereof with the end of the intersecting pipe will define a properly formed weld groove for receiving the weld metal as the tube turn is joined to the intersecting pipe by welding. Even under circumstances where layout and cutting of tube turns is accomplished by experienced workmen, the time required for the layout and cutting operation can be extensive, i.e. in the order of two hours or more. The labor requirement for this operation, therefore, obviously detracts from the commercial feasibility of the construction operation that is being accomplished. It is desirable, therefore, to provide means for accomplishing simple and efficient layout of cutting operations for tube turns, so as to provide properly cut tube turns through involvement of minimum labor and expense. In view of the foregoing, therefore, it is a primary feature of this invention to provide a novel fixture for selectively positioning a tube turn for cutting of the tube turn to a desired included angle and without requiring any layout work for accomplishing the positioning and cutting operation.
It is another feature of this invention to provide a novel fixture for selectively positioning a tube turn and wherein typical pipe cutting apparatus may be employed in conjunction with the tube turn in order to establish a precision cut, thereby ensuring proper beveling of the edge of the tube turn and proper precision cutting of the tube turn to a precise included angle.
It is an even further feature of this invention to provide a novel fixture for cutting of tube turns, wherein a tube turn may be positioned relative to the fixture, locked in assembly with the fixture, whereby the tube turn may be oriented in any suitable position relative to the fixture.
It is another object of this invention to provide a novel fixture for selectively positioning a tube turn for cutting thereof, wherein angular measurement of the cut to be made on the tube turn may be established by means of a simple level, such as is typically available in the field during pipe construction operations.
Other and further objects, advantages and features of this invention will become obvious to one skilled in the art upon an understanding of the illustrative embodiment about to be described and various advantages, not referred to herein, will occur to one skilled in the art upon employment of the invention in practice.